docs(settings): describe the full pythonPath auto-detect order

Author: WilliamSmithEdward

package.json

@@ -37,7 +37,7 @@
           "type": "string",
           "scope": "machine",
           "default": "",
-          "description": "Path to the Python executable used to run the XLIDE backend. Leave empty to use 'python' (Windows) or 'python3' (Mac/Linux) from PATH."
+          "description": "Path to the Python executable used to run the XLIDE backend. Leave empty to auto-detect: a workspace .venv, then (on macOS) well-known install locations such as Homebrew and python.org, then 'python' (Windows) or 'python3' (Mac/Linux) from PATH."
         },
         "xlide.attachToRunningExcel": {
           "type": "boolean",